The present invention relates to competitive techniques for coding and decoding information.
Several coding and decoding methods exist for transmitting images. A distinction is made in particular between main types of coding such as intra coding in which an image is coded autonomously, i.e. without reference to other images, and inter coding in which a current image is coded relative to past images in order to express and send only the difference between those images.
Regardless of the type of coding, numerous coding and decoding functions are available. For inter coding, for example, the coding functions are the various prediction functions that can be used.
A particular coding function is conventionally selected by competition between different available functions with selection being on the basis of a choice criterion or choice function. For example, one standard criterion used in order to arrive at a compromise between quality and bandwidth is the ratio between the distortion resulting from coding and the bit rate.
In standard image coding and decoding environments, this choice is effected unilaterally in the coder. The result of this is the selection of a coding function that must be sent to the decoder each time it changes.
In such implementations, the decoder has a passive role and its calculation and processing capacities are underused.
In particular, in standard systems a large amount of information describing the coding function is used and consumes a non-negligible portion of the bandwidth. What is more, the quantity of descriptive information and the frequency of changes increase with the size of the set of coding functions available.